Boil a large pot of water, and dip the tomatoes in for five seconds each. Peel while still warm (dip again if the skin doesn't come off easily). Seed the tomatoes, and cut into chunks. Put them in a large bowl, sprinkle lightly with salt, and set aside for five minutes.
Add the bread, mozzarella, basil, parsley and garlic to the tomatoes in the bowl. Sprinkle with salt and pepper, toss.
Beat the vinegar into the olive oil. Add water until you have two cups of liquid.
Pour the liquid over the bread salad. At this stage it should look pretty wet. Add a little more water if it doesn't.
Toss well, cover the bowl with a towel, and set aside for an hour.